Wear-resistant connector for a modular link conveyor belt

ABSTRACT

A connector for connecting modular conveyor links to form a belt includes a rod-like core and a powder coating forming a protective shell. The core may be stainless steel and the powder coating may be nylon.

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/713,880, filed Sep. 2, 2005, and U.S.Provisional Patent Application Ser. No. 60/788,650, filed Apr. 3, 2006,the disclosures of which are incorporated herein by reference.

TECHNICAL FIELD

This invention relates generally to the conveyor art and, moreparticularly, to a wear-resistant connector for connecting modular linksto form a conveyor belt.

BACKGROUND OF THE INVENTION

The use of modular link conveyors in industry enjoys increasingpopularity. Particularly for conveying food articles or consumerproducts, especially in packages or in semi-packaged form, the modularlink conveyor represents the overwhelming choice of those in theindustry looking for a long-lasting, low cost conveying solution. In therecent past, significant advances in the development of such have beenmade so as to provide more efficient handling of an even larger varietyof food articles, packages and containers, as well as other types ofarticles and products.

One of the most popular types of modular link conveyor systems on themarket today, if not the most popular, is manufactured and sold by theassignee of the present invention under THE DESIGNER SYSTEM andWHISPERTRAX trademarks, and illustrated and claimed in prior U.S. Pat.No. 4,953,693, Sep. 4, 1990 and U.S. Pat. No. 5,031,757, issued Jul. 16,1991 (both of which patents are fully incorporated herein by reference).Since the time of these early patents in the art, the significantadvances have been fast in coming to provide an even more efficientoperation and better handling and transporting of articles and products.

Despite eliminating the deleterious catenary approach prevalent in theprior art and providing the advantageous secure holding by the guidelinks, an aesthetic problem sometimes arises from use of the preferredstainless steel connector to connect the modular links forming theconveyor belt. Specifically, wear particles, or “black oxide” from theconnector may become embedded in light-colored links made from certainpolymer materials, including Acetal (which, despite being anabrasion-resistant material, is considered to be fairly abrasiveitself). Although not a problem from a durability or reliabilitystandpoint, the resultant appearance of the dark-colored wear particlesembedded in the links can lead to unfounded concerns regardingcleanability of the belt, especially in applications where food productsare being conveyed. Particles separated from the stainless steel rodalso further compound the problem by becoming embedded in the adjacentsurface of the link, which then accelerate the wear.

In the past, others have proposed various types of modular linkconnectors, or “hinge pins” as they are sometimes called, made ofpolymer materials. While such polymer connectors do not create the same“black oxide” as stainless steel, they are not as able to resistsignificant shear loading and are also substantially more susceptible tocreep. Over time, this creep causes polymer rods to assume an irregular,or “wavy,” profile. This profile not only compromises the appearance andoperation of the belt, but also makes it more difficult to remove therods for replacement. Additionally, the dimensional pitch of the chainis lost, resulting in premature sprocket wear.

More recently, U.S. Pat. No. 6,648,129 to Sedlacek describes a “twomaterial” hinge pin arrangement in which a rod made of a rigid material(such as steel) slidably receives a urethane outer tube. According tothe patent, the urethane tube forms a high friction material thatpreferably rotates relative to the underlying rod to facilitatearticulation (ostensibly as the result of particles becoming embedded inthe space between the tube and the rod). Besides creating an arrangementthat can be impossible to clean in an easy and economical fashion, thehigh friction surface of the outer tube may actually cause significantwear on the links, as well as the underlying rod in the event ofrelative rotation.

Accordingly, a need is identified for an improved connector for thelinks in a modular link conveyor belt. The rod should be exceptionallystrong and resistant to the effects of creep, while also being suitablefor use in even the most sensitive of conveying environments (includingthose in which food is transported). The rod should also be easy andinexpensive to manufacture using existing techniques, and thus would notcontribute significantly to the cost of the overall conveyor system(which can include hundreds or thousands of these rods) or its wear. Therod should also be usable with existing conveyors, such as in a retrofitsituation, without changing the design or principles of operation.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the invention, an improvement isproposed for a system in which a first part includes a surface subjectedto wear as the result of sliding frictional contact with a second part.The improvement comprises a powder coating applied to the surface of thefirst part. The powder coating serves to reduce friction between thefirst and second parts, provide enhanced wear resistance to the firstpart, and improve cleanability of the first part.

In one embodiment, the first part comprises metal, such as stainlesssteel, the powder coating comprises a polyamide, such as nylon, and thesecond part comprises a polymer material, such as acetal. Preferably,the second part comprises a link of a chain and the first part comprisesa connector for engaging the link such that sliding friction resultsbetween the first and second parts. For instance, the link may includean opening for receiving the connector such that an outer surface of theconnector including the powder coating frictionally engages a surface ofthe link within the opening. Most preferably, both the first and secondparts are moving relative to each other, but possibly only one of thefirst or second parts is fixed and the other is moving.

In accordance with another aspect of the invention, a connector forconnecting links of a conveyor belt is disclosed. The connectorcomprises an elongated core. A powder coating forms a shell on a surfaceof the core.

In one embodiment, the core comprises steel and, preferably, stainlesssteel. In that or another embodiment, the shell comprises nylon.Alternatively, the shell may comprise a material selected from the groupconsisting of PROTECH CHEMICAL LTD. Mercury Blue hybrid, SHERWINWILLIAMS Whitewater polyester, SHERWIN WILLIAMS Antique White hybrid,THERMOCLAD White DURALON 12 (Nylon 12), THERMOCLAD Clear DURALON 12(Nylon 12), SHERWIN WILLIAMS Furniture White polyurethane, and RILSANnylon. Preferably, the shell is generally clear, but may be white incolor, and further comprises a polymer material including ananti-microbial, anti-bacterial, anti-fungal, or germicidal agent.

In accordance with still another aspect of the invention, an elongatedconnector is provided for connecting links in a conveyor belt. Theconnector comprises a rod-like mild or stainless steel core. A nyloncoating, such as an extruded tube or powder coated shell, is provided ona surface of the core.

In accordance with yet another aspect of the invention, a conveyor beltsection comprises a plurality of links interconnected by an elongatedconnector. The connector comprises a rod-like body including a metalcore and a powder coating forming a shell. Preferably, the linkscomprise acetal, the metal core comprises stainless steel, and thepowder coating comprises nylon.

In accordance with still another aspect of the invention, a conveyorbelt is disclosed. The belt comprises a plurality of links arranged ininterdigitated rows and an elongated connector for connecting the links.The connector comprises a core and a powder coating forming an outershell on the core.

Still another aspect of the invention is a method of forming a connectorfor the links in a conveyor belt. The method comprises powder coating arod to form an outer protective shell on a surface of the rod.Preferably, the method involves powder coating nylon on a steel orstainless steel rod, such as by electrostatically applying nylon powderto a surface of the rod and then heating the rod to cure the powder andform a protective shell.

Yet a further aspect of the invention is a method of manufacturing aconveyor belt section from a plurality of interdigitated links. Themethod comprises coating a surface of a connector with a powder coatingand connecting the interdigitated links with the coated connector.Preferably, but not necessarily, the coating step compriseselectrostatically applying a nylon powder to a surface of the connectorand then heating the connector (such as for a period greater than about15 minutes and at a temperature greater than about 400°° F.). Mostpreferably, the coating step comprises placing nylon over an entireouter surface of the connector, which is preferably a metal rod.

In accordance with still a further aspect of the invention, a method isdisclosed for manufacturing a conveyor belt section from a plurality ofinterdigitated links. The method comprises coating a surface of aconnector with nylon and connecting the interdigitated links with thecoated connector. Preferably, the coating step compriseselectrostatically applying a nylon powder to a surface of the connectorand then heating the connector (such as for a period greater than about15 minutes and at a temperature greater than about 400° F.).Alternatively, the coating step may comprise placing an extruded tubeover the connector, which is preferably a metal rod.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially schematic side view of an overall conveyor system;

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a cutaway, partially cross-sectional view of a wear stripassociated with the guide rail for engaging a side link of the conveyorchain;

FIG. 4 a is a perspective view of an exemplary side link;

FIG. 4 b is a cross-sectional side view of the side link;

FIG. 4 c is a cross-sectional side view of a tab for engaging atransverse connector;

FIG. 5 is a partially cross-sectional end view of the modular linkconveyor system including roller support rails for the upper and lowerruns;

FIG. 6 is a top cutaway view showing the side-flexing capability of oneembodiment of the disclosed conveyor chain;

FIG. 7 is a perspective view showing a connector including a shell orcoating made in accordance with one aspect of the invention;

FIGS. 8-10 are tables illustrating numerically the result of variousexperiments conducted to demonstrate the potential efficacy of theinventive aspects disclosed.

DETAILED DESCRIPTION OF THE INVENTION

Reference is now made to FIGS. 1 and 2, which depict an overallconventional arrangement of a conveyor system S including a belt orchain 10. The chain 10 includes a conveying surface 11 for engaging andsupporting articles. In this particular embodiment, the chain 10comprises or includes modular links including side guide links 12 andintermediate links 13 arranged in spaced apart rows (see FIG. 6 and noterows R₁ . . . R_(n)), which thus partially create the conveying surface11. Adjacent rows R₁, R₂ of links are interconnected by transverselyextending connectors 14, which are also referred to in the vernacular as“cross rods,” “hinge pins,” etc.

With regard to the side links 12, and as perhaps best understood byviewing FIGS. 3 and 4 a-4 c, each may include an outer depending arm 12a and an inwardly projecting or extending transverse tab 12 b (thuscreating different right handed or left handed side links, depending onthe particular positioning). When present, the depending arm 12 a andtransverse tab 12 b are designed to receive a conventional supportstructure, which may include a longitudinally extending guide rail G₁ orG₂ forming part of the conveyor support frame. These guide rails G₁, G₂support the chain 10 along both the forward run F and the return run Ras it is bidirectionally driven in an endless path (such as by spacedsprockets K adapted for engaging the links along a transition from aforward run F to a return run R and gang-driven by an associated motorM).

Each guide rail G₁ or G₂ preferably includes a wear strip W formed of atribologically enhanced material to provide reduced friction contactwith the links 12. The guide rails G₁ or G₂ may be C-shaped or sigmashaped, as shown in FIGS. 2 and 5, or instead may simply include one ormore support sections of any desired shape carrying the associated wearstrips W such that they project outwardly therefrom like a tongue ortenon and thus define a bearing surface for the chain 10 (and, inparticular, the side guide links 12). Associated links of the sortmentioned are typically formed of complementary or matched materials,such as acetal or other inexpensive, lightweight, and durable materialsusing well-known forming techniques (including possibly co-molding ofdifferent materials). Although performance of the system 10 may beimproved as a result, matching of the materials forming the links andguide rails (wear strips) is not considered a requirement.

Preferably, pairs of side links 12 together with intermediate links 13form rows spaced apart in the direction in which the chain 10 istypically driven (referred to as the longitudinal direction or theconveying direction (note action arrow C in the plan view of FIG. 6)),since it corresponds to the main direction in which articles areconveyed by the chain 10 during normal operation, as opposed to thetransverse or lateral direction P). To interconnect the pairs of links12 forming a first (leading) row R₁, the transverse connector 14 takesthe form of a stainless steel rod passing through aligned holes (seeFIG. 6) formed in foot portions 13 c of each intermediate link 13 (whichmay be more than two in cases where each link has plural laterallyrepeating sections), including the side link 12. During construction ofthe chain 10, the links 12, 13 of a second, adjacent (trailing) row R₂interdigitate with those of the first row R₁, with the connector 14passing through a slot 12 d elongated in the conveying direction D andformed in the apex 12 e of each link 12, 13 in the second row (andthereby forming a section of the chain 10).

As should be appreciated by those of skill in the art, this specificstructural arrangement (which is considered entirely optional forpurposes of the present invention in its broadest aspects) allows forthe chain 10 to side-flex to negotiate curves or bends (see FIG. 6), aswell as to compress or expand in the longitudinal direction, and thuseliminates the need for a catenary. If such enhanced functionality isnot necessary for a particular application, the slots 12 e could simplybe replaced with plain holes for receiving the connector 14, which wouldthis result in a non-side flexing, non-longitudinally compressiblechain.

The connector 14 may be retained in place by a retainer 16. In theillustrated embodiment, the retainer 16 is in the form of a tab 17removably inserted in a receiver 12 f or slot formed in each side link12. As shown in FIG. 4 b, the tab 17 may include a recess 17 a forengaging a notched or recessed portion 15 of the connector 14. Thispattern of assembly may be repeated among the interdigitated links 12,13 as necessary to form a chain 10 having a particular length in theconveying direction. A full description of this type of chain or “belt”as it is sometimes called in the vernacular, is found in the commonlyassigned '693 and '757 patents, the disclosures of which are fullyincorporated herein by reference.

With reference to FIG. 7, one aspect of the present invention isproviding the connector 14 for at least one row of links at leastpartially with an outer coating. Specifically, this connector 14 ispreferably formed of a rigid core 14 a formed of an electricallyconductive material, such as one made of mild or stainless steel (e.g.,303 or 304), and coated to create an outer coating or shell 14 bcomprised of a durable, wear and abrasion resistant material. In oneparticular embodiment, the shell 14 b comprises a polyamide, such asnylon, and more preferably Nylon 11 or Nylon 12.

One version of Nylon 12 is distributed in powder form under thetrademark DURALON 12 by the Thermoclad Company of Erie, Pa. Anotherversion of nylon powder is sold under the trademark RILSAN by Arkema,Inc. of Birdsboro, Pa. However, the powder coating may comprise otherdurable, abrasion-resistant materials, with a preference for those thatare polymer-based, such as polyethylene and epoxy coatings, and thoseidentified in the examples provided herein (such as, for example, thefollowing paints: PROTECH CHEMICAL LTD. Mercury Blue hybrid, SHERWINWILLIAMS Whitewater polyester, SHERWIN WILLIAMS Antique White hybrid,and SHERWIN WILLIAMS Furniture White polyurethane).

The outer shell 14 b may be formed by coating the core 14 a, which maybe done by placing (e.g., sliding or extruding) a tube or sleeve formedof nylon material over the outer surface. Preferably, the extruded tubeor sleeve is made of nylon and bonded to the core 14 a, such as by usingan adhesive. However, the coating forming the shell 14 b (which may alsobe considered a film) is most preferably applied to the core 14 a by apowder coating process. Such process involves using an electrostaticdelivery device (e.g., a gun) or fluidized bed to deliver the nylon inpowder form to the entire outer surface of the core 14 a, and thenbaking the powder at a relatively high temperature (e.g., greater than400° F.) for a certain time period (e.g., greater than 15 minutes). Thisbaking cures the powder and forms an outer coating (e.g., the shell 14b). Aside from being relatively easy and inexpensive to implement, thistechnique results in a durable, seamless coating, and one securelybonded to the surface of the core 14 a, without the need to adhesives orthe like (and without any appreciable gap in which food particles,debris, or the like may become trapped).

Regardless of how the shell 14 b forms on the core 14 a and theparticular material used, the resulting coated composite connector 14for use in conveyor belts provides numerous advantages over thosepresently available for such use, especially when the core 14 a is madeof stainless steel. First and foremost, the shell 14 b prevents thedeleterious “black oxide” problem from arising when the core 14 a ismade from stainless steel, including when used with white-colored linksmade of Acetal.

Secondly, even if the shell 14 b is compromised in use, the underlyingstainless steel forming the core 14 a provides an additional layer ofprotection against corrosion. This is especially true where aperforation or scratch arises in a non-wearing area of the connector 14.This is because the thickness and resulting elevation of the remainingnylon tends to prevent direct contact from being made with theunderlying surface of the stainless steel core 14 a.

In the case of nylon, the shell 14 b is also somewhat compliant, atleast as compared to a metal such as stainless steel. Thus, unlike theconventional stainless steel rods, the shell 14 b may act to receive andhold any wear particles that may be generated in an embedded fashion.This capturing helps to prevent wear particles once generated fromembedding in any adjacent surface of the link and causing furtherdeleterious wear on the connector 14, as occurs using the conventionalarrangement.

Aside from being relatively hard (75+/−5 Shore D Hardness, in the caseof Nylon 12) and offering superior abrasion resistance, the shell 14 bwhen made of nylon also has low coefficient of friction, especiallyrelative to other polymer materials from which links may be formed(including acetal). Thus, the shell 14 b does not in any way compromisethe operation or performance of the conveyor belt or chain 10. In fact,aside from eliminating the black oxide problem when used with astainless steel cores it is believed that the properties of the shell 14b will actually extend the service life of the resulting belt byproviding an added layer of protection against the effects of wear.

Finally, many coating materials capable of being used to form the shell14 b, including Nylon 12, are generally food grade and approved by theFDA for use with food products. Thus, providing the coating on the steelcore 14 a made of such FDA-compatible or food grade materials to formthe shell 14 b does not in any way impact the ability of the belt to beused in a conveyor for food products. Moreover, the shell 14 b isbelieved to improve cleanability by providing a uniform, low frictionsurface over which cleaning fluids may freely pass and soft particles(such as debris from food products) do not readily adhere.

Preferably, the material associated with the core 14 a to form the shell14 b is generally clear or translucent (e.g., cloudy but lighttransmissive) once cured. As a result, the coating is generallyinvisible, and the connector 14 appears to be made entirely from steel.This essentially hides the shell 14 b and the existence of the coatingfrom the consumer, and also facilitates retrofitting the coatedconnector into modular link belts or chains without coated connectors.However, it is also possible to make the coating opaque, or otherwisecolor it to match the color of the links forming the conveyor belt(e.g., a white coating for white links).

For food based applications, it may also be desirable to incorporate agermicidal, anti-microbial, anti-bacterial, and anti-fungal agent intothe coating forming the shell 14 b. Consequently, the resulting rod 14would not only be able to resist the growth of undesirable microbes,fungi, germs or bacteria, but would also help to prevent theseundesirable entities from propagating (especially in “hidden” or closedareas where the rod passes through cavities or recesses in the links).Suitable types of such agents may be found in U.S. Pat. Nos. 6,180,039,6,039,964, 5,941,369, and 5,586,643, the disclosures of which areincorporated herein by reference. Alternatively, titanium dioxide havinga small particle size can be incorporated into the powder coating, whichwhen cured and bombarded with UV rays serves to attack both inorganicand organic compounds and turn them into molecules that can beharmlessly washed away using water.

Thus, with reference back to FIGS. 1-6, the system 10 can alternativelybe characterized as including a first part, such as the metal connector14 (preferably formed of stainless steel), with a surface subjected towear as the result of sliding frictional contact with a second part,such as the link 12 or 13 (preferably made of a polymer material and,most preferably, acetal). In such case, a polymer powder coating orshell, such as one made of a polyamide (e.g., nylon) may be applied tothe surface of the connector 14 to reduce friction with the link 12 or13, provide enhanced wear resistance to the connector 14, and improveits cleanability. Accordingly, an outer surface of the connector 14including the powder coating frictionally engages a surface of the link12, 13 within the opening, including during relative movement betweenthe two (such as when both the connector and link are moving relative toeach other, or when the connector moves while the link remains fixed orvice versa).

The following tests demonstrate the efficacy of the proposed invention.

Manufacturing Test

A white polymer-based (DURALON 12 brand Type 12 nylon) powder coatingfrom Thermoclad was applied to an elongated, generally cylindrical fourmillimeter diameter rod made of stainless steel (303) using anelectrostatic gun. The rod with the powder coating was then baked in anoven at a curing temperature of about 400-425° F., for about 15-20minutes.

The resulting composite connector had a durable, seamless shell having athickness of about 0.003 to 0.005 inches. This added thickness would notcontribute significantly to the diameter and thus could be used withexisting links or in a retrofit situation.

Painting Test

In order to assess the potential to powder coat stainless steel, avariety of different powder coat paints were tried. These included thefollowing paint types:

1. PROTECH CHEMICAL LTD. Mercury Blue hybrid

2. SHERWIN WILLIAMS Whitewater polyester

3. SHERWIN WILLIAMS Antique White hybrid

4. THERMOCLAD White DURALON 12 (Nylon 12)

5. THERMOCLAD Clear DURALON 12 (Nylon 12)

6. SHERWIN WILLIAMS Furniture White polyurethane

All of these powder-coat paint types were successfully applied to thestainless steel rods and should provide adequate performance in terms ofpreventing the creation of the black oxide.

Conveyor Test

Two identical conveyors were assembled using a conveyor test bedallowing two parallel conveyors to operate identically. One conveyor wasassembled using standard stainless steel rods. The other conveyor wasassembled using standard stainless steel rods that had been coated withan Antique White hybrid powder coat paint produced by SHERWIN WILLIAMS.This test was designed to determine if the black oxide formation couldbe prevented by introducing a material between the acetal links and thestainless steel.

After continuous operation of the test bed was started, black oxideformation was observed on the bare stainless steel rods within a fewdays. This black oxide formation has continued to progress throughoutthe bare-stainless-steel-rod chain. No black oxide formation was notedon the chain with rods coated with the hybrid powder coat paint for 7½weeks with only brief (less than one hour) interruptions to observe theprogress.

Accelerated Abrasion Test

In order to test aggressively the abrasion resistance of the powdercoating, rods were mounted in a holder, immersed in a sand/water slurrybath, and the assembly rotated continuously. This results in rapid wearof the rods. As described below, a total of three different tests havebeen conducted.

In the first test four different powder coat materials applied to astainless steel rod were tested along with a bare stainless steelcontrol rod.

The four materials were:

1. SHERWIN WILLIAMS Whitewater polyester paint

2. SHERWIN WILLIAMS Antique White hybrid paint

3. THERMOCLAD White DURALON 12 (Nylon 12)

4. SHERWIN WILLIAMS Furniture White polyurethane paint.

After less than 2 hours of operation, the polyester, hybrid, andpolyurethane paints had all been worn through to the underlyingstainless steel. The Nylon 12 and the bare stainless steel rods showedsubstantially less wear. FIG. 8 shows a summary of the total wear oneach of the six rods that were tested.

The second test was a direct comparison of the Nylon 12 coating and thebare stainless steel. A total of approximately eight hours of testingresulted in the stainless steel rods and the Nylon 12 coated rodsshowing essentially identical wear rates. FIG. 9 shows a summary of thetotal wear on each of the six rods that were tested.

A third test was conducted to evaluate white DURALON 12 applied byElectrostatic Technology, Inc. of Branford, Conn., clear DURALON 12applied using an electrostatic gun, and bare stainless steel. This testwas conducted for a total of approximately seven hours.

Again, the stainless steel rods and two (DURALON 12 (2) and clear (1))of the Nylon 12 coated rods showed essentially identical wear rates. Theremaining two Nylon 12 coated rods (DURALON 12 (1) and clear (2)) wereworn through to the metal and had the coating peeled back. As a result,the wear measurements for these two test pieces show that they had morewear than would occur during normal use over a significant period. Itseems likely that the peeling away is simply the extension of thefailure process. FIG. 10 summarizes the total wear on each of the sixrods tested.

Oscillating Wear Test

In order to test the ability of various types of powder-coat materialsto resist abrasion wear an oscillating-wear test machine was set up.This machine is designed to test a variety of different ways that therods may move relative to the acetal links.

Three different powder coat materials or paints were placed into themachine to test along with a standard stainless steel rods. The threematerials were:

1. SHERWIN WILLIAMS Whitewater polyester

2. SHERWIN WILLIAMS Antique White hybrid

3. THERMOCLAD White DURALON 12 (Nylon 12)

A review of the condition of the rods and the links in the test machineapproximately one month after the test began revealed no visuallyapparent wear on any of the coated rods. A subsequent inspection a weeklater showed that the bare stainless steel rods were beginning to showthe presence of black oxide while all of the coated rods showed no blackoxide. Thus, all three of the tested paints appear to prevent theformation of the black oxide. Additionally, they have at least initiallyadequate resistance to wear.

The foregoing description of various embodiments of the presentinvention have been presented for purposes of illustration anddescription. The description is not intended to be exhaustive or tolimit the invention to the precise forms disclosed. Obviousmodifications or variations are possible in light of the aboveteachings. For instance, although there is a definite preference forcoating the entire core 14 a to form the connector, it is possible toprovide the coating strategically to cover only areas of contact (andthus wear) with the links. Likewise, the coating need not be applied inany notches, recesses, or indentations in the connector that will notcontact with the link surface in use. Although a cylindrical rod isdisclosed as the connector, it may have any desired cross-sectionalshape or form. The embodiments described provide the best illustrationof the principles of the invention and its practical applications tothereby enable one of ordinary skill in the art to utilize the inventionin various embodiments and with various modifications as are suited tothe particular use contemplated. All such modifications and variationsare within the scope of the invention.

1. In a conveyor system having a first conveyor part with a surfacesubjected to wear as the result of sliding frictional contact with asecond conveyor part, the improvement comprising: a powder coatingapplied to the surface of the first conveyor part to form a durableouter shell substantially over the entirety of the first conveyor partwithout a gap between the outer shell and the second conveyor part inwhich food particles or debris may become trapped, whereby the outershell serves to reduce friction between the first and second conveyorparts, provides enhanced wear resistance to the first conveyor part bypreventing surface contact with the material underlying the outer shell,and improves cleanability of the first conveyor part.
 2. The system ofclaim 1, wherein the first part comprises stainless steel.
 3. The systemof claim 1, wherein the powder coating comprises a polyamide.
 4. Thesystem of claim 1, wherein the powder coating comprises nylon.
 5. Thesystem of claim 1, wherein the second part comprises a polymer material.6. The system of claim 1, wherein the second part comprises acetal. 7.The system of claim 1, wherein the second part comprises a link of achain and the first part comprises a connector for engaging the linksuch that sliding friction results.
 8. The system of claim 7, whereinthe link includes an opening for receiving the connector such that thesurface of the connector including the powder coating frictionallyengages a corresponding surface of the link within the opening.
 9. Thesystem of claim 1, wherein one of the first or second parts is fixed andthe other is moving.
 10. A method of manufacturing a conveyor beltsection from a plurality of interdigitated links, comprising: providinga surface of a connector with a powder coating to form a durable outershell without a gap between the connector and the outer shell in whichfood particles or debris may become trapped; and connecting theinterdigitated links with the coated connector.
 11. The method of claim10, wherein the providing step comprises electrostatically applying anylon powder to a surface of the connector and then heating theconnector.
 12. The method of claim 10, wherein the heating step is for aperiod greater than about 15 minutes and at a temperature greater thanabout 400° F.
 13. The method of claim 10, wherein the providing stepcomprises placing nylon over an entire outer surface of the connector.14. A method of manufacturing a conveyor belt section from a pluralityof interdigitated links, comprising: providing an outer surface of asteel connector with a nylon coating to form a durable outer shellwithout a gap between the outer shell and the steel connector in whichfood particles or debris may become trapped; and connecting theinterdigitated links with the coated connector.
 15. The method of claim14, wherein the providing step comprises electrostatically applying anylon powder to a surface of the connector and then heating theconnector.
 16. The method of claim 15, wherein the heating step is for aperiod greater than about 15 minutes and at a temperature greater thanabout 400° F.
 17. In a conveyor for conveying articles in a conveyingdirection, said conveyor having a first link having a surface subjectedto wear as the result of contact with a generally cylindrical stainlesssteel connector for connecting the first link with a second link, theimprovement comprising a powder coat applied to the surface of thestainless steel connector to form a durable outer shell without a gapbetween the outer shell and the connector in which food particles ordebris may become trapped.
 18. The conveyor according to claim 17,wherein the powder coat comprises nylon.
 19. The conveyor according toclaim 17, wherein the stainless steel connector further includes atleast one notch.
 20. In a conveyor system having a plurality ofinterdigitated links connected by a metal connector rod having a surfacesubjected to wear as the result of sliding frictional contact with oneor more of the links, the improvement comprising a powder coatingapplied to the surface of the metal connector rod to form a durableouter shell without a gap between the connector rod and the outer shellin which food particles or debris may become trapped, whereby the outershell serves to reduce friction between the links and the connector rod,provides enhanced wear resistance to the connector rod, and improvescleanability of the connector rod.
 21. In a conveyor system having aplurality of interdigitated links connected by a steel connector rodhaving a surface subjected to wear as the result of sliding frictionalcontact with one or more of the links, the improvement comprising anylon powder coating applied to the surface of the connector rod to forma durable outer shell without a gap between the connector rod and theouter shell in which food particles or debris may become trapped,whereby the outer shell serves to reduce friction between the links andthe connector rod, provides enhanced wear resistance to the connectorrod, and improves cleanability of the connector rod.
 22. A method ofmanufacturing a conveyor belt section from a plurality of interdigitatedlinks, comprising: providing an electrically conductive connector rodfor interconnecting the interdigitated links; electrostatically applyinga powder to a surface of the connector; heating the power to form aprotective outer shell; and connecting the interdigitated links with thecoated connector to form the conveyor belt section.
 23. A method offorming a connector for connecting a plurality of interdigitated linksto form a conveyor belt section, comprising: providing a steel rod forforming the connector for connecting the interdigitated links;electrostatically applying a powder to a surface of the steel rod; andheating the powder to form a protective outer shell without a gapbetween the steel rod and the outer shell in which food particles ordebris may become trapped, whereby the outer shell, in use, serves toreduce friction between the links and the connector rod, providesenhanced wear resistance to the connector rod, and improves cleanabilityof the connector rod.
 24. The improvement for a conveyor systemaccording to claim 1, wherein the outer shell is seamless.